This invention relates generally to energy saving devices and more particularly concerns the reduction of electrical energy demands of smaller or moderate consumers.
More sophisticated electrical energy consumers are well aware of the impact of power factors on power demand. A low plant power factor will require an available capacity much greater then is actually used. Therefore, to avoid premium charges applied to low power factor customers, the large consumer will "correct" its overall power factor by adding to its system a load which draws the opposite kind of reactive power. Normally, the existing reactive power is inductive, caused by motors, transformers, fluorescent lights and the like, resulting in a lagging kvar (kilovolt amperes reactive). Thus a corrective bank of capacitors is added to the system, providing a leading kvar to balance the system.
The analysis of overall system impedance to determine the corrective load needed to adjust the power factor toward unity is for the most part not within the knowledge or economic capability of the smaller or moderate consumer. As a result, they generally continue to operate at uncorrected power factor levels, drawing more current than actually needed for their load and absorbing the cost of correspondingly larger heat losses in their system.
However, perfect matching of reactive power is not necessary to achieve a savings in energy costs. Significant savings can be achieved by approximation of balancing kvar with respect to individual loads in the overall system. Approximate power factor correction of an induction motor will reduce heat losses and lengthen motor life as well as increase available capacity for other loads in the system. Thus smaller plants, commercial facilities and even residences could benefit by application of corrective reactive loads to most machines, air conditioners and refrigeration units, pumps and the like if a single, cost effective, easily selectable, power factor corrective load were available.
Every consumer has the ability to readily ascertain the nameplate data of inductive motors used in their system. An understanding of the meaning of that data is not necessary to achieve an approximate power factor correction if a standard approximate corrective load corresponding to that data is available. No such device is known on the market today.
Therefore, it is an object of this invention to provide a standardized series of capacitor load devices from which a device effective to correct the power factor of a motor can be selected solely by reference to the known horsepower, phase and voltage of the motor. It is also an object of this invention to provide a standardized series of capacitive load devices in which multiples of the standardized devices can be readily combined for adaptation to specific requirements. It is a further object of this invention to provide a standardized series of capacitive load devices in which the capacitive elements are employed in multiples readily adaptable to single or three phase operation. And it is an object of this invention to provide a standardized series of capacitive load devices that may be easily installed by the user.